1. Field of the Invention
The present invention relates to a method of estimating the preferred orientation of a polycrystalline material using an X-ray diffraction method.
2. Description of the Related Art
Methods of estimating the preferred orientation of a polycrystalline material utilizing X-ray diffraction phenomena include a qualitative technique through measurement of the full width of half maximum in a rocking curve, and a quantitative technique in which the orientation distribution function (ODF) is calculated with the use of pole measurement.
According to the former technique by which the full width of half maximum is determined, there are problems in that the preferred orientation can not be quantitatively determined, and such a weak preferred orientation as to exhibit no peak in the rocking curve can not be estimated. But, this technique still has been practically used, in which a lot of samples are measured with the same measuring apparatus under the same measurement conditions, and the obtained full widths of half maximum are relatively compared with each other. However, it is very difficult to compare the full widths of half maximum, which are determined with different measuring apparatus or under the different measurement conditions, with each other. Because the full widths of half maximum depend on measurement optical systems so that the reliability of the absolute values is low.
The latter pole measurement technique has problems in that a goniometer having a complicated structure including a χ axis is required, and it takes much time to measure. Also, in this case, weak orientation can not be quantitatively estimated, because of the correction of an X-ray irradiation area and the complicated calculation of the back ground.
Japanese Patent Publication No. 5-1999 A (1993) discloses a technique which uses a theoretical diffraction intensity calculation formula. This technique is, however, limited to the estimation of the change in the degree of preferred orientation in the direction of a sample thickness, and accordingly the changes in the degree of preferred orientation in the preferred orientation of a sample itself can not be absolutely quantified.